The present invention relates generally to mitigating cross-interference between communication devices in wireless communication systems, and more particularly to systems capable of wirelessly interfacing with several communication device types.
Wireless connectivity for a communication device may be enabled using a medium access control (MAC) and physical layer (PHY) specification within a particular area. Specifically, based on the MAC and PHY specification, access to one or more frequency bands over a communication channel for the purposes of local area communication may be provided. For example, wireless connectivity may be provided to automatic machinery, electronic equipment, or communication devices, which may be fixed, portable, hand-held and/or mobile within a local area.
Although the current focus is on the individual integration of wireless communications technologies into a wireless-enabled platform, it may be beneficial for more than one of these technologies to co-exist in one system. In this way, two or more communication device types may wirelessly interface with a wireless communication system, for example, a wireless-enabled personal computer (PC) system.
A number of short-range and long-range wireless communications technologies, such as Bluetooth or IEEE 802.11, may lend themselves to potential integration with one another in a single wireless communication system. The Bluetooth standard is described in detail in documents entitled “Specifications of the Bluetooth System: Core” and “Specifications of the Bluetooth System: Profiles”, both published on July 1999, and are available from the Bluetooth Special Interest Group on the Internet at Bluetooth's official website. The IEEE 802.11 standard is described in detail in a specification entitled “IEEE Std 802.11 1999 Edition,” available from IEEE Customer Service Center, 445 Hoes Lane, P.O. Box 1331, Piscataway, N.J. 08855-1331.
While these wireless communications technologies have been fairly well defined in the context of individual usage models, their joint usage models with respect to each other are not yet clearly defined. For instance, it is conceivable to have applications where two or more of these communications technologies may have to operate in tandem or concurrently on the wireless-enabled platform.
Unfortunately, such integration may result in undesired interference between the active radio systems, leading to potential signal loss and/or malfunction of the radio system themselves. A cross-interference problem may occur with the integration of multiple radio devices into a wireless communication system, as an example.
Because of the cross-interference problem, integration of wireless communications technologies (e.g., radio frequency (RF) based) into a PC platform may be difficult to accommodate. Therefore, in some cases a simple implementation of multiple integrated radio systems may not be feasible at all. Moreover, based on a certain combination of usage models or other limitations imposed by original equipment manufactures (OEMs), integration of two or more radio technologies into the PC platform may become even more difficult.
A variety of mechanisms have been contemplated to reduce cross-interference problem between multiple radio devices within a system. Traditional ways of dealing with this problem involve circuits for gain control and filter tuning to reject interference signals.
In particular, a set of complex analog circuits is required to obviate the cross-interference. Typically, such complex analog circuits are used for out-of-band frequency rejection using filter tuning, and gain control, using up valuable hardware real estate. Further, a complex signaling mechanism (e.g., sideband signaling) may need to be deployed in order to support and/or coordinate the filters/gain control circuits, resulting in inefficient usage of available communication bandwidth.
Thus, reduction in cross-interference is desired for communication systems that wirelessly interface with multiple communication devices.